The (Ba · ·FCH³) Photofragmentation Channels: Dynamics of the Laser Induced Intrachister (Ba · ·FCH₃) → + BaF + CH3 and Ba + FCH₃ Reaction

Abstract

The spectroscopy and dynamics of the intermediate species between reac-tives and products of chemical reactions, i.e. the transition state region [1], have been the subject of several studies in recent years [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]. There are different experimental approaches to gain insight into this part of the potential energy surface: Zewail’s group has probed these short-lived states in real time using femtosecond lasers [4]. Another approach pioneered by Soep and co-workers [5, 6, 7, 8, 9, 10] and by Wittig and co-workers [11, 12] is to study photoinduced chemical reactions in van der Waals molecules, were the reaction surface is accessed directly by laser excitation of the complex. The reactants are oriented and the set of impact parameters is limited by the complex geometry. Soep and co-workers studied the Hg··Cl2 and the Ca··HX (X = halogen) complexes, monitoring the yield of the electronically excited product, while Wittig and co-workers substituted the metal by a molecule as for example in the HI··OCO complex. Unfortunately, the reaction dynamics information obtained from these specific van der Waals approaches where product action spectra are measured, is somewhat blurred by the (normally) unknown spectroscopic factors controlling the laser excitation from the ground (non-reactive) up to the excited (reactive) van der Waals potential.

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